US News discovered an interesting loophole with American Express' new Bluebird online banking initiative: you can use any rewards credit card to buy money at specific retailers and essentially get those rewards for free. Here's how it works:

The Bluebird account is reloadable by purchasing Vanilla Reload cards at certain retailers. Those who have credit cards that earn large amounts of cash back at these retailers can proceed to buy Vanilla Reload cards and refill their Bluebird accounts. Then the Bluebird account can be used to pay for purchases that don't earn cash back.

One caveat: some retailers have caught on to this loophole and have started to require cash as the only payment method for these reload cards.

If retailers are starting to catch on (like they often do), we'll probably see this loophole closed quickly. Nevertheless, it's worth a shot. You can always call the store in advance and ask. (To find retailers who sell Vanilla Reload cards, go here.) The worst that can happen is they say no, and the best is that you have a means of earning a free vacation, getting some bonus cash, or have a method of obtaining a cash advance through your credit card without paying any direct fees.